In the separation-science art, there often is a need to dispense separation-science membranes in a manner that prevents them from being contaminated. This need is particularly pronounced when the separation-science membrane is a sorptive membrane such as a polytetrafluoroethylene (PTFE) disc or cellulosic membrane. Sorptive membranes must be handled with care to avoid sorbing compounds that would taint the separation analysis. In spite of this need for avoiding contamination, separation-science membranes, including sorptive membranes, often are packaged in a manner that requires the membranes to be physically lifted from the container by the user's fingers or by use of a small instrument such as tweezers. The Nuclepore.TM. Corporation (Pleasanton, Calif.) places its PTFE (Filinert.TM.) and cellulosic (Membra-Fil.TM.) discs in plastic containers that have a recessed storage chamber. To facilitate removal of an individual disc, a sidewall of the recessed storage chamber opens into a cavity that provides space for a person to insert their finger or a tool to grip an individual disc. Whatman International Ltd. (Maidstone, England) and others use similar containers to store and dispense their separation-science media.
Apparatuses have been disclosed that dispense tablets, bingo chips, and other discs without having to physically lift each disc from its storage compartment. Examples of such apparatuses are shown in U.S. Pat. Nos. 4,792,057, 4,619,376, 4,413,750, 4,216,878, 4,004,719, 3,467,277, 3,410,385, 3,115,992, 2,567,089, and 2,493,616. U.S. Pat. No. 2,493,616 published in 1950, in particular, discloses a portable dispensing unit 10 that obviates the necessity of a person touching the tablets with his hands. The device as shown in FIG. 1 of that patent has a body portion 11 that has a storage chamber 12. A sliding cover 18 has a pocket 19 for receiving a tablet 28 from chamber 12 when the pocket is in communication with the chamber. By sliding the cover 18 to expose the pocket 19, a tablet 28 can be discharged from the dispensing unit 10.